Ceramics such as silicon carbide are brittle in nature and have little plastic deformability even at high temperature. A number of brazing techniques have been developed for joining ceramics such as silicon carbide; however, no ceramic braze exists which has a melting point in the temperature range desired for silicon carbide and which is suitable for use in a high neutron flux environment. In such an environment, for example, within a fusion reactor, the effects of neutron-induced swelling and neutron activation must be taken into consideration. These become particularly important considerations for silicon carbide bodies which are presently under investigation for prospective use as first wall structural materials in a fusion reactor. Moreover, chemical compatibility between the brazing materials, the silicon carbide structures and the operating environment are other important factors that must be taken into consideration.
Therefore, the search has continued to develop improved brazing compositions for adequately joining dense silicon carbide bodies, particularly bodies that will be employed in a high neutron flux environment.